2014-07-30T11:07:22ZNew data from borehole strainmeters to infer lava fountain sources (Etna 2011-2012)http://hdl.handle.net/2122/9024
Title: New data from borehole strainmeters to infer lava fountain sources (Etna 2011-2012)
Authors: Bonaccorso, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Currenti, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Linde, A.; Department Terrestrial Magnetism - Carnegie Institution, Washington; Sacks, S.; Department Terrestrial Magnetism - Carnegie Institution, Washington
Abstract: In January 2011 eruptive activity resumed at Etna producing a new phase with frequent lava fountain episodes until April 2012. In November 2011, the first two borehole strainmeters were installed, which detected negative strain changes (~ 0.15 - 0.8 strain) during the paroxysmal events. A Finite Element Model was set up to estimate accurately the tilt and volumetric strain, taking into account the real profile of the volcano and the elastic medium heterogeneity. The numerical computations indicated an elongated depressurizing source located at 0 km b.s.l., which underwent a volume change of ~2 x 106 m3 which is the most of the magma volume erupted while a smaller remaining part is accommodated by the magma compressibility. This shallow source cannot accumulate large magma volumes and, thus, favours short term periodic eruptive events with a fairly constant balance between the refilling and the erupted magma.2012-12-31T23:00:00ZProbabilistic modeling of future volcanic eruptions at Mount Etnahttp://hdl.handle.net/2122/8958
Title: Probabilistic modeling of future volcanic eruptions at Mount Etna
Authors: Cappello, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Bilotta, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Neri, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Del Negro, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia
Abstract: The statistical analysis of volcanic activity at Mt Etna was conducted with the twofold
aim of (1) constructing a probability map for vent opening of future flank eruptions and
(2) forecasting the expected number of eruptive events at the summit craters. The
spatiotemporal map of new vent opening at Etna volcano is based on the analysis of spatial
locations and frequency of flank eruptions starting from 1610. Thanks to the completeness
and accuracy of historical data over the last four centuries, we examined in detail the spatial
and temporal distribution of flank eruptions showing that effusive events follow a
nonhomogenous Poisson process with space-time varying intensities. After demonstrating
the spatial nonhomogeneity and the temporal nonstationarity of flank eruptions at Etna, we
calculated the recurrence rates (events expected per unit area per unit time) and produced
different spatiotemporal probability maps of new vent opening in the next 1, 10 and
50 years. These probabilistic maps have an immediate use in evaluating the future timing
and areas of Etna prone to volcanic hazards. Finally, the results of the analysis of the
persistent summit activity during the last 110 years indicate that the hazard rate for eruptive
events is not constant with time, differs for each summit crater of Mt Etna, highlighting a
general increase in the eruptive frequency starting from the middle of last century and
particularly from 1971, when the SE crater was formed.2013-05-07T22:00:00ZCompositionally zoned crystals and real-time degassing data reveal changes in magma transfer dynamics during the 2006 summit eruptive episodes of Mt. Etnahttp://hdl.handle.net/2122/8929
Title: Compositionally zoned crystals and real-time degassing data reveal changes in magma transfer dynamics during the 2006 summit eruptive episodes of Mt. Etna
Authors: Kahl, M.; Institut für Geologie, Mineralogie & Geophysik, Ruhr-Universität Bochum, Bochum 44780, Germany; Chakraborty, S.; Institut für Geologie, Mineralogie & Geophysik, Ruhr-Universität Bochum, Bochum 44780, Germany; Costa, F.; Earth Observatory of Singapore, Nanyang Technological University, Singapore 639798, Singapore; Pompilio, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia; Liuzzo, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Viccaro, M.; Dipartimento di Scienze Biologiche, Geologiche e Ambientali— Sezione di Scienze della Terra, Università di Catania, Corso Italia 57, Catania 95129, Italy
Abstract: One of the major objectives of volcanology
remains relating variations in surface monitoring signals to
the magmatic processes at depth that cause these variations.
We present a method that enables compositional and temporal information stored in zoning of minerals (olivine in
this case) to be linked to observations of real-time
degassing data. The integrated record may reveal details
of the dynamics of gradual evolution of a plumbing
system during eruption. We illustrate our approach using the
2006 summit eruptive episodes of Mt. Etna. We find that the
history tracked by olivine crystals, and hence, most likely
the magma pathways within the shallow plumbing system of
Mt. Etna, differed considerably between the July and
October eruptions. The compositional and temporal record
preserved in the olivine zoning patterns reveal two mafic
recharge events within months of each other (June and
September 2006), and each of these magma supplies may have
triggered the initiation of different eruptive cycles (July 14–24
and August 31–December 14). Correlation of these observations with gas monitoring data shows that the systematic rise of
the CO2/SO2gas values is associated with the gradual (preand syn-eruptive) supply of batches of gas-rich mafic magma
into segments of Etna’s shallow plumbing system, where mixing with pre-existing and more evolved magma occurred.2013-01-29T23:00:00ZVolatiles in pantellerite magmas: A case study of the Green Tuff Plinian eruption (Island of Pantelleria, Italy)http://hdl.handle.net/2122/8840
Title: Volatiles in pantellerite magmas: A case study of the Green Tuff Plinian eruption (Island of Pantelleria, Italy)
Authors: Lanzo, G.; Università di PAlermo, Dip, Scienze della Terra e del MAre; Landi, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia; Rotolo, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia
Abstract: The Green Tuff (GT) Plinian eruption, the largest in magnitude at Pantelleria, erupted 3 to 7 km3 DRE of
pantellerite magma and a small volume of trachyte. Fifty-nine anorthoclase-hosted melt inclusions from the
two basal pumice memberswere analyzed by FT-IR spectroscopy in order to assess the pre-eruptiveH2Ocontent
in the pantellerite melt. Microanalytical methods were used to determine major element, Cl, F and S contents.
Melt inclusions and glassy groundmasses have a nearly homogeneous pantelleritic composition (peralkaline
index = 1.9-2.2) and variable water contents ranging from 1.4 to as high as 4.2 wt %, i.e. much higher than
the 1.4 wt % of earlier published studies. The chlorine content is constant at about 1 wt %. Combined Cl and
H2O data were used to estimate a confining pressure of about 50 MPa (depth around 2-3 km) for the GT
magma chamber. The chamber was characterized by a compositional zoning with a dominant pantellerite
overlying a trachyte magma. Soon after the GT eruption, intra-caldera volcanism was dominated by the
eruption of voluminous trachyte lava flows, while pantellerite melt production resumed after about 20 ka
with numerous low-volume, mildly explosive (Strombolian) to effusive eruptions. Comparison with data
from the literature reveals that, despite the different explosivity, the post-caldera Strombolian eruptions
and the GT Plinian eruption were fed by pantelleritic magmas with similar water contents. Chlorine and
CO2 contents suggest that the young magma reservoirs feeding the Strombolian to effusive activity were
deeper (h ≥ 4.5 km) than the much larger (based on erupted volumes) magma chamber which fed the
GT eruption.2013-08-31T22:00:00ZMonitoraggio sismico del territorio nazionale: stato dell'arte e sviluppo delle reti di monitoraggio sismicohttp://hdl.handle.net/2122/8813
Title: Monitoraggio sismico del territorio nazionale: stato dell'arte e sviluppo delle reti di monitoraggio sismico
Authors: Sergio, Guardato; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia
Abstract: Il sistema CUMAS (Cabled Underwater Module
for Acquisition of Seismological data) è un
prodotto tecnologico-scientifico complesso nato
con il Progetto V4 [Iannaccone et al., 2008] allo
scopo di monitorare l’area vulcanica dei Campi
Flegrei (fenomeno del bradisismo).
Si tratta di un modulo sottomarino cablato e
connesso a una boa galleggiante (meda elastica). Il
sistema è in grado di acquisire e trasmettere alla
sala di monitoraggio dell’OV, in continuo e in
tempo reale, sia i segnali sismologici sia quelli di
interesse geofisico ed oceanografico (maree,
correnti marine, segnali acustici subacquei,
parametri funzionali di varia natura).
Il sistema è in grado di ricevere comandi da remoto
per variare diversi parametri di acquisizione e di
monitorare un cospicuo numero di variabili di
funzionamento.
Il sistema si avvale del supporto di una boa
galleggiante attrezzata. La boa è installata a largo
del golfo di Pozzuoli (Napoli) a circa 3 km dalla
costa. Il modulo sottomarino, collegato via cavo
alla parte fuori acqua della boa, è installato sul
fondale marino a una profondità di circa 100 metri.2010-12-31T23:00:00ZThe vague volcano-seismic clock of the South American Pacific marginhttp://hdl.handle.net/2122/8744
Title: The vague volcano-seismic clock of the South American Pacific margin
Authors: Scalera, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia
Abstract: During his trip on the Beagle, Charles Darwin
wrote about the eruptions associated with the Concepci´on
earthquake of 1835. A later survey by Lorenzo Casertano,
following the great 1960 Chilean earthquake, identified some
unclear evidence of a link between eruptions and the seismic
event, although some reservations were also raised. Using
data available in 2006 in the Smithsonian Institution
Catalogue of volcanic eruptions, Scalera revealed grounded
evidence that South-American Wadati-Benioff zone earthquakes
of magnitudes greater than 8.4 are associated with
an increased rate of volcanic eruptions, but it was still impossible
to determine a causal link between the two phenomena.
An average return period of about 50 yr was deducible
from the data for the time window 1800–1999. After
2006, the Smithsonian Institution’s effort to improve our
knowledge of this region has greatly increased the completeness
of the catalogue, adding the eruptions from the 2000–
2010 interval, together with 50% more new entries in the
list of Andean volcanoes. The great Chilean Maule earthquake
of 27 February 2010 (M = 8.8), occurring exactly five
decades after the 1960 event, provided an occasion to reanalyse
this updated database. The results suggest a preferential
causal eruptions-earthquake relationship, but additional future
volcano-seismic events should be studied to arrive at
a definitive conclusion, within the perspective of using this
phenomenon for Civil Protection. The possible correlation of
South American volcano-seismic events with the Markowitz
oscillation of the Polar Motion is another good reason for
trying to establish an integrated geodynamic explanation.2012-12-31T23:00:00ZThe Volcano-Seismic Clock of the South American Pacific Margin - A Possible First Link Between Natural Disasters Prevention and Expanding Earthhttp://hdl.handle.net/2122/8662
Title: The Volcano-Seismic Clock of the South American Pacific Margin - A Possible First Link Between Natural Disasters Prevention and Expanding Earth
Authors: Scalera, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia
Editors: Scalera, Giancarlo; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia
Abstract: A volcano-seismic correlation was for a long time suspected to occur on the
Pacific margin of South America. Scalera (2008) using the data available in 2006 in the
Smithsonian Institution Catalogue of the volcanic eruptions, has revealed evidence that
earthquakes happened into the South-American Wadati-Benio zone – with magnitude
greater than 8.4 –are associated to an enhanced rate of volcanic eruptions, but has been
impossible to determine the causal chain between the two phenomena. After 2006, the effort
of the Smithsonian Institution to improve our knowledge of this region has resulted in
a greatly increased completeness of the catalogue, adding the new eruptions for the 2000-
2010 interval, but also an additional 50% of new entries in the list of the Andean volcanoes.
The occurrence of the Chilean earthquake of Maule – 27 February 2010 (M=8.8); occurred
at five decades from the 1960 quake – has been the occasion to rework all the data searching
for additional clues able to indicate a preferred causal direction eruptions-earthquakes
or earthquakes-eruptions – or from a third more general cause (e.g. a mantle movements) to
both eruptions and earthquakes. This short note discusses the three above-said hypotheses
and tries to establish if these results could be useful to the aims of the Civil Protection in
the programs of prevention and/or forecasting of natural disasters.2012-11-30T23:00:00ZEnhanced crystal fabric analysis of a lava flow sample by neutron texture diffraction: A case study from the Castello d’Ischia domehttp://hdl.handle.net/2122/8609
Title: Enhanced crystal fabric analysis of a lava flow sample by neutron texture diffraction: A case study from the Castello d’Ischia dome
Authors: Walter, J. M.; Mineralogisch-Petrologisches Institut, Universität Bonn, Poppelsdorfer Schloss, D-53115, Bonn,; Iezzi, G.; Dipartimento di Ingegneria e Geologia (INGEO), Università G. d’Annunzio, Chieti, Italy; Albertini, G.; Dipartimento di Fisica e Ingegneria dei Materiali e del Territorio, Università Politecnica delle Marche,; Gunther, M. E.; Department of Geological Sciences, University of Idaho, Moscow, Idaho, USA; Piochi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Ventura, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Jansen, E.; Mineralogisch-Petrologisches Institut, Universität Bonn, Bonn, Germany; Fiori, F.; Di.S.C.O., Sez. di Biochimica, Biologia e Fisica, Università Politecnica delle Marce, Ancona, Italy
Abstract: The crystal fabric of a lava has been analyzed for the first time by neutron texture diffraction. In this
study we quantitatively investigate the crystallographic preferred orientation of feldspars in the Castello
d’Ischia (Ischia Island, Italy) trachytic exogenous dome. The crystallographic preferred orientation was
measured with the monochromatic neutron texture diffractometer SV7 at the Forschungszentrum Jülich in
Germany and a Rietveld refinement was applied to the sum diffraction pattern. The complementary thin
section analysis showed that the three-dimensional crystal shape and the corresponding shape preferred
orientation are in agreement with the quantitative orientation distributions of the neutron texture data. The
(0k0) crystallographic planes of the feldspars are roughly parallel to the local flow bands, whereas the other
corresponding pole figures show that a pivotal rotation of the anorthoclase and sanidine crystals was active
during the emplacement of this lava dome. In combination with scanning electron microscopy investigations, electron probe microanalysis, XRF, and X-ray diffraction, the Rietveld refinement of the neutron diffraction
data indicates a slow cooling dynamic on the order of several months during their crystallization under
subaerial conditions. Results attained here demonstrate that neutron texture diffraction is a powerful tool that
can be applied to lava flows.2013-01-30T23:00:00ZReply to comment by D. Carbone and D. Patanè on “Multi-disciplinary investigation on a lava fountain preceding a flank eruption: the 10 May 2008 Etna case”http://hdl.handle.net/2122/8341
Title: Reply to comment by D. Carbone and D. Patanè on “Multi-disciplinary investigation on a lava fountain preceding a flank eruption: the 10 May 2008 Etna case”
Authors: Bonaccorso, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Cannata, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Corsaro, R. A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Di Grazia, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Gambino, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Greco, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Miraglia, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Pistorio, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia
Abstract: Bonaccorso et al. [2011a] investigated the source and magma dynamics of the 10 May 2008 lava fountain at the South-East Crater (SEC) of Mount Etna through a multidisciplinary approach that integrated a wide data set ranging from bulk rock compositions of the erupted products to seismic tremor and long-period events, tilt and gravity signals. Using a large dataset, the study provided a robust framework in which the mechanism of the 10 May 2008 lava fountain is explained as a violent release of bubble-rich magma layer previously trapped at the top of a shallow reservoir located between −0.5 and 1.5 km above sea level (asl). This result is in agreement with recent relevant literature [Allard et al., 2005; Vergniolle and Ripepe, 2008; Aiuppa et al., 2010; Andronico and Corsaro, 2011; Bonaccorso et al., 2011b; Calvari et al., 2011; Vergniolle and Gaudemer, 2012].
In the introduction of their comment Carbone and Patanè [submitted] affirm that in their opinion the interpretation that “the lava fountain was generated by the fragmentation of a foam layer trapped at the top of shallow reservoir” is not soundly based. This comment’s conclusion is puzzling because one of the comment’s authors (D. Patanè) is also a co-author on the paper by Aiuppa et al. [2010] where the same conclusion, now criticized, was well supported (see figure 5 and conclusions of that paper). In particular, in the conclusions Aiuppa et al. [2010] reported that “The paroxysmal SEC episodes mark the violent release of a bubble-rich magma layer, with bubbles having relatively shallow reservoir ...", that is, the same conclusion now criticized in the comment. After this, the comment raises issues concerning the analysis and interpretation of gravity and tilt data in the multidisciplinary approach presented by Bonaccorso et al. [2011a]. The comment by Carbone and Patanè is divided into 4 paragraphs, labelled “1. Introduction”, “2. Gravity changes”, “3. Tilt changes” and “4. Concluding remarks” with only paragraphs 2 and 3 containing specific comments. In this reply, we address these two paragraphs, and we shall show how the assumptions underlying the comment are merely speculative and why the results presented by Bonaccorso et al.[2011a] remain valid.2011-12-31T23:00:00ZComment on "Multidisciplinary investigation on a lava fountain preceding a flank eruption: The 10 May 2008 Etna case" by A. Bonaccorso et al.http://hdl.handle.net/2122/8327
Title: Comment on "Multidisciplinary investigation on a lava fountain preceding a flank eruption: The 10 May 2008 Etna case" by A. Bonaccorso et al.
Authors: Carbone, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Patanè, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia
Abstract: The paper "Multidisciplinary investigation on a lava fountain preceding a flank eruption: The 10 May 2008 Etna case", by Bonaccorso et al. (2011), presents a multi-parameter dataset encompassing the eruptive episode featured in the title. Through the dataset at their disposal, the authors tried to set constraints on the coupled phenomena which governed the paroxysmal event and subsequent flank eruption. Even though the joint analysis of different data offers considerable potential to extract additional information on the dynamics behind the observed phenomena, the most obvious implication is the risk of not treating all the available information with due care, which may lead to misinterpretation of the data.
In the following, we discuss issues concerning the analysis and interpretation of gravity and tilt data in Bonaccorso et al. (2011) and show why, in our opinion, the conclusion that "all the data concur in indicating that the 10 May lava fountain was generated by the fragmentation of a foam layer trapped at the top of a shallow reservoir" is not soundly based.2011-12-31T23:00:00Z